Cohesion And Adesi

Water attached to one another (cohesion) because water is polar. Water has a partial negative charge (σ-) near the oxygen atom due to electron pairs (almost) not be shared, and some partial positive charge (σ +) near the oxygen atoms. In water this happens because the oxygen atom is more electronegative than hydrogen atoms, which means, he (oxygen atoms) has a more "tensile strength" of electrons that is shared within the molecule, pulling the electrons closer to him (also means attract the negative charge of electrons are) and make the area around the oxygen atom is more negatively charged than the areas around the two atoms of hydrogen.

Water has also adesi high character due to the nature of its polar.
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Water has a large surface tension caused by the strong nature of the cohesion between water molecules. This can be observed when small amounts of water are placed in a surface that can not be too wet or too dissolved (non-soluble); water will come together as a trickle. On a glass surface is very clean or very soft water
surface can form a thin layer (thin film) because the force of molecular attraction between the glass and water molecules (adhesion force) is stronger than the cohesion force between water molecules.

In biological cells and organelles, water in contact with the membrane and surface proteins that are hydrophilic, ie, surfaces that have a strong attraction to water. Irvin Langmuir observed a strong repulsive force between hydrophilic surfaces. To make a surface hydrophilic dehydration - in the sense of release layer strongly bound water of hydration - need to be really working against these forces, called hydration forces. These forces will be very great value, but decays rapidly in the range of nanometers or smaller. Importance of these forces in biology has been studied extensively by V. Adrian of the National Institutes of Health. [11] These forces is particularly important when cells are dehydrated when in direct contact with the dry outer space or cooling outside the cell (extracellular Freezing).